+ 1Prince wrote:Just to clarify something here. The front M3 ant roll bar attaches to the shock. There is a mount for this on the shock but only the M3s have this mount. A lot of coilovers come with the attachments some if you've fitted coilovers you may be able to upgrade. The M3 anti roll bar is thinner because it attaches to the shock it is less unsprung weight.
from the various research I have been doing for the purposes of our 328 sport track car I can confirm the following:
1. The difference in ARB diameter front M3 vs. 328 is due to the different type/amount of leverage achieved by mounting the drop link against the shock body (M3) vs. the wishbone (328). If the leverage and therefore amount of tension achieved is higher in the M3 setup, then one can achieve a stiffer setup with a smaller diameter ARB (e.g. M3).
2. If you buy an E36 M3 suspension/coilovers, the option will be there to use an M3 droplink and attach the 328 ARB or the M3 ARB to the shock body. If you use the thicker 328 bar mounted to the shock body you will achieve higher tension than the M3 ARB (bay way of the difference thickness between the two) using the same mounting method and therefore higher resistance to roll.
3. Too stiff an ARB setup can and will overpower street based springs. The effect can be seen on track where the unloaded front or rear wheel lifts off the ground, this is the effect of the spring/suspensions not being stiff enough to cope with the stiffer ARB's and collapsing to near full compression under load. There is allot of talk on Yank forums about this behaviour with tracked cars.
4. Adjustable Rose jointed Front and Rear drop links can be sourced from various places for the M3 setup (also advertised as suitable for the non M cars) including Ebay. These can be used to adjust the tension of a front or rear ARB to give the same effect as fitting a stiffer bar, or buying an adjustable ARB from Eibach etc. The former is the cheaper option, plus it's race spec engineering and less likely to suffer failures like rubber bushes.
I'm personally of the opinion that money is better spent on a "decent suspension", stiffer springs and quality dampers, with emphasis on the quality dampers which will do significantly more to control corner lean/wallow than an ARB setup. To give you an idea of the budget end of a quality suspension/dampers think KW Clubsport and up through AST, Nitron, Bilstein B16/PSS16 Clubsport, to Ohlins at the top end. HSD Monopro and below do not fall into the decent damper variety I'm afraid, they are cheap because the most important part (the dampers) are cheap and cheerful with lack of decent control, adjustability, consistency and durability.
Feedback received from serious track addicts that the ideal which is also streetable is the PSS16 Clubsport (all quality setups are streetable though imo, unless you go racing stiffness springs for the road), but at north of 3K for PSS16 the suspension it is not justifiable for most when compared with the value of the car.......Until you've had a ride in a car with one fitted and then you'll be trying to figure out how to sell the wife for 3K+
Hope this helps somebody.